Some times we need to keep jobs running without a
ssh session, here there are three ways to achieve this. I suggest to learn a terminal multiplexer in long term, it’s really useful when you have long time working on Linux/Unix system.
The best and simplest way is:
nohup long-running-command &
It was made specifically for this, by default it will log stdout to
nohup.log, if standard output is not a terminal, logs will be appended to
~/nohup.log. If you want to specify the output log into a different file:
nohup COMMAND > FILE
More details can refer to
man nohup. What
nohup does, is to effectively separate the process from the terminal:
- It closes standard input (the program will not be able to read any input, even if it is run in the foreground. it is not halted, but will receive an error code or
- It redirects standard output and standard error to the file
nohup.out, so the program won’t fail for writing to standard output if the terminal fails, so whatever the process writes is not lost.
- It prevents the process from receiving a
SIGHUP(thus the name).
If you already have started the program and don’t want restart it, we can use
ctrl+z to stop current execution and then use
bg to resume it and switch the running program to background (We can use
fg to pull the job to frontground)
Finally we use
disown to remove the process from the shell’s job control.
So, even you logout from a
ssh session, the program will still keep running in background.
We have three choices for this, [[screen]], [[tmux]], and [[byobu]].
tmux is mostly used ones. On Ubuntu or Debian system, we install it with:
sudo apt-get install screen sudo apt-get install tmux
Byobu is an enhancement for the GNU Screen, you can install it with this commands:
sudo add-apt-repository ppa:byobu/ppasudo apt-get updatesudo apt-get install byobu